New gravel, dead neons

[GeorgeBlevins]

I've had a bare 40 gallon breeder with potted plants in it for about 3 years, with only two goldfish in it. Three weeks ago I decided to give away the goldfish and trade it for the community route. It was stocked with 1 bleeding heart tetra (only 1 was available, waiting on school), 4 black neons, 6 neons, and 6 cory cats <1". Everyone was doing great, water was stable.

Last night I washed and added 40 lbs of black gravel, did a 30% water change, and added two adfitional plants. No fertilizers were added. Detritus got a little stirred up but not too cloudy, and it settled pretty quickly.

This morning 3 neons were dead, 1 is swimming around weakly, and 2 are missing (likely dead, but I can't find them?). Black neons & bleeding heart look fine, cories seem lethargic. I did another 30% water change and checked the parameters, was shocked to see 0 ppm ammonia, 0 ppm nitrite, 0 ppm nitrate. Water is at 78 degrees. So what on earth is going on?

 

[Autumnsky]

Sorry to hear that.

By washing do you mean rinsing with water type thing or any cleaners or additives? Just have to ask.

What kind of gravel is it?

Seems odd.

Are you using test strips or liquid test kit?

 

[GeorgeBlevins]

Its imagitarium brand gravel. I rinsed 2 cups of gravel at a time until the water ran clear.
I'm using a liquid test kit.

The other fish are still fine, which is a relief.

 

[m.j.gomez]

Hello, when rinsing gravel did you treat it w/water conditioner to neutralize any chlorine & chloramine in tap water before adding? Cause w/0 ammonia, 0 nitrite & 0 nitrates(should be some nitrates in cycled tank)sounds like your cycle may have crashed.
You may have to redo a fish in cycle. If this is situation hold off on getting more neons theyvare notoriously sensitive to bad water conditions. Hope this helps you!

 

[GeorgeBlevins]

No, I used such a huge amount of water in the process of rinsing, dechlorinating it all would probably be impossible.
I didn't realise the amount of chlorine on the pebbles after rinsing would be enough to crash the tank. I also added dechlorinator at the same time I added gravel, since I was doing a 30% water change. I always treat for the whole 40 gallons when I do a water change.

 

[m.j.gomez]

When adding rinced gravel I usually leave a little water in it & add conditioner to that before adding. Just was thinking some untreated water got into filter(if running) & killed some or all bacteria in it(causing crash).

 

[GeorgeBlevins]

That might have been it, I'll do another test today and see what's going on.
Thanks for your advice!

 

[mishyc]

When doing water changes, you only treat the water that’s going in with the amount that’s going in, if you know what I mean! For example, if you are putting 10 gallons in, put the required amount of dechloronator for 10 gallons in the untreated water before putting in the tank. If you are putting 40 gallons worth of treatment in every time you change water, you will be overdosing

 

[GeorgeBlevins]

Thanks for the reply.

I treat the whole tank because I use a python hose to pour water directly in and out from the sink. I know a lot of folks who do this without problems.

 

[mishyc]

Oh, so you put untreated water in the tank and then treat it? In surprised the fish aren’t bothered by it

 

[m.j.gomez]

Thanks for the reply.

I treat the whole tank because I use a python hose to pour water directly in and out from the sink. I know a lot of folks who do this without problems.

Hello again, i usually shut down filters even if I dose whole tank. I don't like taking a chance that things may not go as planned. I've had most of my pets for 3+yrs & become very attached to them!!!!!

 

[King Fisher]

Thanks for the reply.

I treat the whole tank because I use a python hose to pour water directly in and out from the sink. I know a lot of folks who do this without problems.

I agree. As long as you dose the tank then add water directly it will dechlorinate within seconds. It does seem to work well.
Dosing for the entire tank size when doing this would be my practice as well.